Urodynamic device and procedure

ABSTRACT

A method performed by a computer correlates vesicoelastic pressure data (10, 12, 14) with volume data and calculates vesicoelastic work performed by the bladder (20), wherein the amount of vesicoelastic work performed by the bladder (20) is determined by calculating an area under said vesicoelastic pressure data (10, 12, 14) when said vesicoelastic pressure data (10, 12, 14) is correlated against the volume data.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Utility Application claims priority to aPCT Application Number PCT/US16/60241 filed Nov. 3, 2016, which furtherbases priority to provisional application numbers 62/250,344 filed Nov.3, 2015 for a URODYNAMIC AND UROFLOWMETRY DEVICE AND PROCEDURE, and62/261,863 filed Dec. 2, 2015 entitled URODYNAMIC AND UROFLOWMETRYDEVICE AND PROCEDURE, the entirety of the above referenced applicationsare hereby incorporated by reference.

BACKGROUND

Urinary tract and bladder problems are prevalent amongst men and womenof all ages and throughout the world. Such ailments include overactivebladder and underactive bladder where the detrusor muscle of the bladderactuates prematurely before the bladder is filled or not enough afterthe bladder is filled. This may be caused by dysfunction of the detrusormuscle itself or the nerve response that triggers urination(micturition). Many other bladder and urinary tract issues exist aswell. Pharmaceutical companies and medical device companies haveinvested in and developed an array of drugs and products to diagnose andtreat these issues.

On the pharmaceutical side of the industry, various companies offerprescription drugs designed to counteract the abnormal behaviors of thebladder. Likewise, medical device companies provide various productssuch as catheters and others designed to be used in urodynamic studies.The use of these products aid physicians and clinicians in theidentification and treatment of bladder related issues.

Notwithstanding the investment, pharmaceutical and medical devicecompanies have encountered many difficulties in defining quantifiableobjective criteria to determine that treatment is effective. Presentparameters that are readily available for use today such as complianceand measuring uninhibited bladder contractions are routinely open forsubjective interpretation and prone to inter and intra rater variabilityeven within the same sample at different times. This renders thesecriteria less than perfect for clinical practice and for clinicaltrials.

Conventional urodynamic principles for identifying bladder issuesinvolve filling the bladder with a solution such as a saline solutionwhile measuring pressure vs. time while the bladder is being filled. Acatheter is inserted through the urethra and into the bladder (see FIG.5 for example) and the saline solution is passed through the catheter.The pressure is measured by the catheter through a pressure sensoreither built into the catheter or measured as transmitted pressure in apressure sensing module outside the patient. External software chartsthis pressure versus time. The output from the catheter is graphed and aphysician then inspects the graph to qualitatively analyze the pressurevariations over the time scale associated with the fill to visuallyguestimate whether fluctuations in pressure indicates an abnormalbladder condition or whether treatment is effective. The methodology, insome instances, involves the physician using calipers to painstakingly,physically measure spikes in the graph. Compliance is measured manuallyand the location of the maximal volume and pressure is eyeballed torepresent the place most likely to have been not associated with adetrusor contraction. These processes can be long and uncertain.Likewise, in drug trials, the same procedure is used over multitudes ofdifferent graphs from numerous patients to, again, guestimate theefficacy of a particular drug to a bladder problem. The presentinvention was developed in light of these and other issues.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a system for performing a urodynamicprocedure according to one aspect of the invention;

FIG. 2 is a schematic view of a system for performing a urodynamicprocedure according to one aspect of the invention;

FIG. 3A is a schematic view of a system for processing data according toan aspect of the invention;

FIG. 3B is a schematic view of a system for processing data according toan aspect of the invention;

FIG. 4 is a schematic view of a urodynamic system according to an aspectof the invention;

FIG. 5 is a graphical view of a pressure versus volume curve for oneaspect of the invention;

FIG. 6 is a flowchart according to an aspect of the present invention;

FIG. 7 is a flowchart according to an aspect of the present invention;

FIG. 8 is a graphical view of a pressure versus volume curve for oneaspect of the invention;

FIG. 9 is a graphical view of a pressure versus volume curve for oneaspect of the invention;

FIG. 10 is a graphical view of a pressure versus volume curve for oneaspect of the invention; and

FIG. 11 is a schematic view of a system for performing a urodynamicprocedure according to one aspect of the invention;

FIG. 12A is a graphical view of a pressure versus volume curve for oneaspect of the invention;

FIG. 12B is a graphical view of a pressure versus volume curve for oneaspect of the invention;

FIG. 13 is a flowchart according to an aspect of the present invention;

FIG. 14 is a flowchart according to an aspect of the present invention;

FIG. 15A is a schematic view of a bladder according to an aspect of thepresent invention; and

FIG. 15B is a schematic view of a bladder according to an aspect of thepresent invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to FIG. 1, an embodiment of a device and procedure forconducting urological testing according to one aspect of the presentinvention is shown and described. In FIG. 1, a urological testing system9 is shown including a bladder catheter 11 and a rectal catheter 13connected respectively to pressure transducer 101 and pressuretransducer 103 respectively. The bladder catheter, in one embodiment,pumps a saline solution generally the same in concentration andcomposition to that of rectal catheter. However, one skilled in the artwill recognize alternate fluids that may be used instead of the salinesolution described herein.

Referring now to FIG. 2, the application of the urological testingsystem 9 to a bladder 20 will now be shown and described. Bladder 20 isshown having a catheter end 28 inserted therein. The catheter end 28 isinserted through the urethra and into fluid communication with theinterior cavity 25 of the bladder 20. Physiologically, the describedbladder is a human (male or female) bladder but also may be that of ananimal. The bladder 20 generally includes bladder walls 22 that definethe cavity 25. A detrusor 26 is a muscle encircling the bladder walls 22that actuates to constrict the bladder walls when an amount of urine inthe interior cavity 25 reaches a predetermined pressure sensed by nervessurrounding the bladder walls, resulting in release of the interiorsphincter muscle 23 and external sphincter muscle 35 to result inurination or micturition to expel the urine in the cavity 25 through theurethra.

With continued reference to FIG. 2, the catheter end 28 is generally adual channel cylindrical element that includes a pressure sensingchannel with an exposed region 105 and a channel with an opening 107 forinfusion of liquid 31 therein. The catheter includes channel 105A that,at one end, connects to exposed region 105 and, at a second end,connects to pressure transducer 101. The pressure sensor may also beprovided in a separate channel at the tip of the catheter. In thepresent embodiment, the bladder catheter 11 is part of the catheter end28 such that the saline solution flows through a passage in the catheterend 28 and into the bladder 20 during fill.

The catheter in the present embodiment includes a second channel 107Athat connects opening 107 to pump 109 such as a centrifugal pump. Pump109 is fluidly connected to the previously mentioned saline solution andacts to pump the solution through the second channel 107A, through theopening 107 and into the bladder during the procedure.

The pressure transducer 101 can be any standard pressure sensor such asthose employing a diaphragm positioned between a vacuum or knownpressure and the saline solution in the bladder. In one aspect, apiezoelectric generated output voltage is created based on thedeflection of the membrane against a piezoelectric element. The pump 109in one embodiment is a scaled or calibrated pump that outputs a signalthrough lead 111 to computer 38 representing the volumetric flowrate ofsaline into the bladder. However, instead of a calibrated pump, aseparate volume sensor, in one embodiment, is in the form of avolumetric flow sensor that measures the flow rate of fluid through theaperture in the second channel 107A and reports that value to aprocessing device or the computer to associate that flow with a timescale and calculate the volume per unit time. In another aspect, thecross section of the aperture in the second channel 107A or the opening107 is known and the pressure can be used to calculate flow rate. Oneskilled in the art will recognize other means for calculating volume andflow rate.

The pressure sensor and the volume sensor provide an analogue outputsignal to the signal line 111 that, in turn, feeds to analog to digitalor A/D converter in computer 38. The A/D converter converts the analogueoutput to digital and provides that digital signal to computer 38. It isalso recognized that computer 38 may receive the analogue signal andconvert it internally to a digital signal through an appropriate I/Oport and drivers.

With reference to FIG. 11, to calculate volume during voiding (when thepatient is expelling urine instead of during filling of the bladder), auroflow voiding device 130 is used. The uroflow voiding device 130 isconnected to computer 38 by the data line 111A to similarly provide datarepresenting the volumetric flowrate exiting the bladder during voidingor micturition. If one knows the starting volume in the bladder, thevolumetric flowrate can be used to calculate current volume of thebladder at a particular time or at a particular pressure in the bladder.The system shown in FIG. 11 may be replaced by any known volumetricflowrate system, such as a catheter inserted into the patient, thatmeasures the flowrate of urine being expelled from the bladder.

Computer 38, in one aspect, employs a timing or synchronizing feature orother methodology to be used to coordinate the pressure, volume of thebladder and time components such that the pressure and volume can beassociated with or charted against a time scale of the fill. In anotheraspect, the pressure is correlated with or charted against (i.e. thepressure at each volume point during fill) the volume of the bladder asshown in FIG. 4. In one example of the present invention, once voidingbegins or micturition starts at line 90, then the system may be pausedwhile the patient is connected to the system of FIG. 11. Or, the patientis switched to the system of FIG. 11 once the urge to urinate begins.Thereafter, the process resumes and the pressure is measured against thevolume or time as desired as the volume reduces or time passes. Forexample, with reference to FIG. 9, the volume increases as shown byarrow 122 until reaching line 120. Line 120 can be at a point at or tothe right of line 90 or generally left of the max pressure andrepresents the beginning of micturition or when the patient has the urgeto urinate. The pressure increases with actuation of the detrusor andthen voiding begins and the volumetric flowrate is measured by thesystem of FIG. 11 until reaching zero. By knowing the volumetricflowrate from the measurement, the volume of the bladder is calculatedat each point of time and correlated to the pressure at thattime/volume. By this way, the volumetric flowrate, time, volume andpressure can all be correlated and thereby charted.

It will be understood that any known urological testing may beundertaken with the present invention and the described embodiments arenot limited to the specific testing described herein. Additionally,instead of real time data provided to the computer 38 during testing,the present invention may be used with data files from previouslyundertaken urological testing, whether in graph or data format that arelater uploaded through any known means to computer 38.

In the same fashion described with respect to the bladder, it will beunderstood that rectal pressure and time may also be obtained in therectum for reasons that will be described. The pressure is provided froma catheter end in the rectum in a similar way to the computer 38. Aswill be discussed later, the use of the rectal pressure is used incombination with the bladder pressure to obtain a true bladder pressure.

Referring now to FIG. 3A, computer 38 is described in greater detail. Inone embodiment, computer 38 is a conventional computing system thatincludes a main processor 40 with an arithmetic logic unit, control unitand memory and a cache memory 43. A data bus 45 provides a plurality ofI/O ports that connect display 48 and main memory 44. The display may bea LCD, touch or other display. I/O port 46 is for receiving eitheranalogue information from signal line 111 and 111A.

Software operating in computer 38, in one aspect, is described withrespect to software stack 50 in FIG. 3B. Software stack 50 includes auser interface or UX 52 that is a rendered image providing results ofthe analysis, input and output features for entering requisiteinformation into the program that may be entered by a user or physician.The UX may be a PC or mobile platform UX (connecting to a server throughweb APIs or other means). An application layer 54 is provided that doeshigh level processing and normalization of data, sending and receivingdata and communicating with the UX 52. Application layer may be providedthrough client side or a combination of client and server sideapplication and scriptin, on premise or cloud based. Database 56 is anystandard database (SQL, Oracle or others) that maintains data in atablature format, provides data modeling and retrieval capabilities.Libraries and support programs 58 provide additional support, analytics,data mapping, graphing and math functions or other libraries andfunctions as required or called by application layer 56. I/O 60 providesdrivers and other software needed to communicate, convert or otherwiserecognize data provided to computer 38 (such as pressure or volume data)as well as outputs to controllers or other peripherals such as thedisplay. Finally, operating system or OS provides all needed operatingsystem functions as required.

With continued reference to the figures, one embodiment of the operationof the present invention is shown and described. A physician orassistant thereto injects the saline solution from bladder salinecontainer 15 into bladder 20 through the catheter 11 and catheter end 28as previously described. Likewise, saline solution from the rectalcatheter is injected into the rectum of the patient. The bladder 20 isfilled with saline 24 at a continuous rate (i.e. 10 cc/min) in oneexample. The bladder pressure is referred to as the vesical pressure andthe rectal pressure is termed the abdominal pressure. The subtractedpressures of vesical minus abdominal are termed the detrusor pressure orthe actual pressure of the bladder. The bladder is filled untilmicturition occurs or until pain is experienced by the patient or unsafebladder pressures are reached. Such pressure is charted against volumeboth during filling and voiding.

Work in thermodynamics for a closed cavity is represented by dw=Pdv.Thus, the change in work is equal to the pressure times the change involume. Accordingly, the inventors have determined that the work done bya bladder (or done when filling or voiding the bladder) is equal to themathematical integral of the aforementioned equation or otherwise statedW=∫₀ ^(V) Pdv where V is the final volume and P is the pressure for eachdelta V. Further, the inventors have determined that such work atvarious sections of a P v V (pressure v volume) curve may result inimproved and more quantitative means for determining whether thedetrusor muscle is actuating too frequently, for example, which would berepresented by an increased amount of work or, in the case ofunderactive bladder, where the detrusor muscle is not actuating enoughat certain stages (such as during micturition). This means that if oneis to plot the pressure vs the change in volume, the work done by thebladder is the area under that curve or Σp×v where for each volume pointalong the fill. Linearly, this can also be written as c×Σp×t where c isa constant that converts the linear time value into the volume value(say by knowing the constant volumetric flowrate of the pump 109).Therefore, one aspect of the present invention is to determine the workdone by the bladder from the area under a pressure vs. volume curve(hereinafter referred to as a urodynamic curve) and use that work todetermine abnormality of bladder functions.

In FIG. 4, the AUC (area under curve) is shown with respect to oneexample urodynamic curve. The urodynamic curve is representative of abladder and the area under the curve (AUC) is proportional to the totalwork being performed by the bladder. In the graph of FIG. 4, the X axisrepresents change in volume as the bladder is filled while the Y axisrepresents the bladder pressure exerted at the various points during thefill and subsequently during voiding.

With continued reference to FIG. 4, another aspect of the presentinvention is the ability to delineate different components of aurodynamic curve. More specifically, the urodynamic curve is broken upin areas representing different phases of bladder activity duringurological testing. As such, the inventors have recognized that theamount of work done at various sections of the P v V curve relate todifferent bladder dysfunctions. Generally speaking, in healthy bladders,the pressure during the initial phase of the fill is generated byelastic characteristics of the bladder. Later, the detrusor activatesand the bladder pressure is a function of both the detrusor and theelastic characteristics. Accordingly, the present invention in oneaspect breaks up the urodynamic curve up into several components thatrepresents when only the elastic conditions should occur and when thedetrusor actuates. Therefore, different forms of work done are measuredby measuring the area under the curve (AUC) at different regions alongthe curve.

When the detrusor actuates, the amount of work AUC DC represents whetherthe detrusor is providing sufficient force to expel urine or whetherthere may potentially be an underactive bladder condition. AUC MVErepresents the vesicoelastic conditions of the bladder and whether thereis sufficient rigidity in the bladder to exert elastic expulsion of theurine. Abnormally large amounts of work may represent blockages or otherimpediments to urination. Dividing the total work by the total change involume provides a representative average pressure exerted or seen by thebladder. Such division by total volume can also be applied specificallyto the AUC MVE to understand the average pressure from the vesicoelasticregion, the AUC DC to understand the detrusor average pressure or thetotal of the two to understand the average total pressure exerted duringthis phase.

More specifically, an elastic component, collagen and muscular componentin the bladder walls (and muscle tissue of the detrusor) combine to forma combined component that will be defined as the Muscular andVesicoelastic (MVE) component in the present invention. The MVEcomponent relates to the elastic characteristics of the bladder.Therefore, the AUC of this portion of the curve is the vesicoelasticpower or work performed by the elastic, collagen and muscle fibers inthe bladder. In healthy bladders, this component makes up the fillingphase prior to a detrusor 26 contractions that occur once the volume inthe bladder reaches a certain amount. The muscular vesicoelasticcomponent is defined to have reached its maximum exclusive of anycontractions of the bladder where lines 10 and 12 meet. At line 12, thevesicoelastic component remains stable and constant (applyingapproximately the same pressure) while the bladder either beginsexpelling urine or continues to increase in volume slightly until thesphincter opens at which point micturition occurs. During this phase andafter actuating the detrusor, the pressure approaches its peakcontraction pressure (line 16) and then it decays (line 14 shows thevesicoelastic component and line 92 represents the detrusor+thevesicoelastic portion) after opening of the sphincter as the bladdercontractions subsides during expulsion of the fluid therein. During thislast phase, the detrusor is still working against an outlet resistanceand therefore work is being done at this point. The MVE component isrepresented by line portions 10, 12 and 14 in FIG. 5 where the line 10,12 and 14 demarcates detrusor bladder contractions (above the line) fromthe MVE component (below the line). The lines illustrating this point ofdemarcation increase (line 10) during initial fill and then flatten(line 12) where the detrusor activates up to the peak of the contractionwhich is depicted by line 16. From line 16, the muscular viscoelasticcomponent shown by line 14 decays as tension in the bladder degradeswith the contraction (segment 3) of the bladder during expulsion of thefluid from the bladder.

Some pressure v volume curves continue to show the volume increasingeven after micturition occurs. This is a function of the graph beinggenerated as a function of time and then being converted to volume basedon the constant multiplied for the volumetric pump. For purposes ofunderstanding, the volume is reversed once the detrusor actuates suchthat the measure is the measure of voiding of the bladder. This mayhappen by stopping the procedure once micturition is detected or thepatient desires to urinate and then connecting the patient to load celluroflowmetry device (see FIG. 11). It can also be accomplished bycombining two urofloemetry tests (one for filling and one for voiding)or any other known means. Flowmeters can be conveniently positionedbeneath a commode or free-standing to accommodate a patient's typicalvoiding position (see FIG. 11 for example). By this way, the volume flowrate of urine exiting the patient's bladder can be detected and, asdiscussed previously, the pressure in the bladder may be measured andplotted there against. The result is the graph shown in FIG. 4 to theright of line 90 that charts pressure against a reducing volume duringvoiding.

Each of the line portions 10, 12 and 14 is illustrated as if it were aHookian linear relationship even though it is understood that there issome non linear degradation due to the nature of the bladder and itselastomer characteristics. Accordingly, it is understood andcontemplated by the present invention that line segments 10, 12 and 14may be illustrated as nonlinear to reflect this relationship.Accordingly, the area under the curve between zero pressure and lines10, 12 and 14 is depicted in FIG. 2 as AUC_(MVE) and generallyrepresents bladder compliance or work done by the MVE component of thebladder.

AUC_(BC) is the area bounded by lines 10 and line 76 during the initialfill phase prior to normal actuation of the detrusor in response toreaching the threshold volume to cause expulsion. The work performedhere is due to detrusor (bladder contractions which are occurringspontaneously and not generating enough force to empty the bladder).These are commonly called uninhibited contractions and are an importantfeature that the present invention identifies for accuracy of medicaldrug trials and to measure the efficacy of medications and treatmentsthat involve the bladder and the elimination of detrusor contractions.

AUC_(DC) is the area bounded by the line portion 12 and line 76. Thisrepresents the detrusor contractions that are used to empty the bladder.The area below the line portion 12 in this figure is the AUC_(MVE) andabove it is the work being used to empty the bladder by the detrusor(AUC_(DC)).

Total work done by the bladder is AUC_(T)=AUC_(MVE)+AUC_(BC)+AUC_(DC). Aratio or percentage would be calculated for each of these component suchas:

${\frac{{AUC}_{VE}}{{AUC}_{T}} + \frac{{AUC}_{BC}}{{AUC}_{T}} + \frac{{AUC}_{DC}}{{AUC}_{T}}} = 1$

Referring now to FIG. 6, a process is depicted for execution by computer38 and software stack 50 to obtain the AUC values for a urodynamicscurve and present those results to provide a meaningful outputrepresenting characteristics of a bladder in a quantitative way. In FIG.6, the process begins in step 64 by the computer 38 receiving data fromcatheter end 28 as discussed previously. The data can be receiveddirectly by I/O 46 through a serial, USB or other port or can be loadedeither manually or automatically as a file such as flat text file. Dataformatting can be in any known way. In one example, the file is in theform of a CSV, TSV OR TXT file. The file may be uploaded and stored viaan uploader on the UX that pulls the files stored from memory or a realtime port connection to the catheter end for real time processing.

In step 66, the data received in the previous step is normalized byapplication layer 54 to ensure it is in proper and consistent format sothat it can be processed by the application layer 54. In step 68, thedata is then loaded into an array type element, database tables, otherdata model or some other means that is formatted to readily make eachpressure and volume and associated time value available for the desiredprocessing. The data may either reside in volatile memory 43 or in adatabase in memory 44 so that it can be recalled or invoke additionaldata processing features. In one aspect, the data model correlates theretrieved pressure values with the corresponding volume and time valuesso that each pressure point is known for its corresponding time andvolume point. In step 70, the data in the data model is then processedby the application layer 54.

Referring now to FIGS. 7 and 8, the processing in step 7 will bedescribed in greater detail. In step 80 of FIG. 7, the maximum pressurevalue is identified through comparison of all pressure values receivedand referenced or stored. The pressure values may be smoothed orprocessed to ensure no unusual values throw calculations off. This canbe accomplished through a number of means including a comparison of allthe pressure values to identify the maximum. This maximum valuecorresponds to the pressure at line 16 in FIG. 8. In step 84, linearregression is then used to identify a best fit line that resides at thebottom points of the pressure values that were stored in the data model.The data points associated with this best fit line are also stored inthe data model. The best fit line is denoted in FIG. 8 as line 10(corresponding to line 10 in previous FIGs). By adjusting the best fitline to fit the lower points of the pressure fluctuations and to filterfor unusual downward or upward spikes, the generated line 10 closelyresembles the vesicoelastic characteristics of a normal bladder (withoutthe detrusor spikes where the detrusor actuates prematurely duringfilling) during the fill phase. As such, the application layer 54employs the processor 40 to, different from standard regression, providea line fitting the bottom points of the graphed data and not just themidpoints of the graphed data. For example, the line 10 reflects whatthe bladder should be doing prior to micturition if there was notpremature detrusor activity occurring. The best fit line 10 extends todetrusor line 90. In one aspect, movable points are positioned along theline 10 to allow a physician or expert to adjust the line 10 to bestsuit such expert's understanding of how the line 10 should look and tobest fit the data given the spikes and their expert opinion in thematter. For example, points movable through click events can be draggedand dropped to different positions to change the line to better reflectthe vesicoelastic conditions. This can be accomplished through scriptingin the rendered view in the UX through, for example, javascript or D3 topermit adjustment of the rendered image and post back to the server torecalculate values to be discussed below.

Detrusor line 90 is represented in the figure as a point along thevolume data where transition from line 10 to 12 occurs. The initiallocation is arbitrary by placing it at a point that likely correspondsto this point. Alternatively, the software looks at the slope of thegenerated line 10 and identifies an increased slope or spike at a laterposition along the volume curve and determines that this is wheremicturition or detrusor actuation occurs. Alternatively, the line can beset if the data is being collected real time when the testing switchesfrom filling to voiding. As will be described later, the line is movableto permit adjustment by a physician to permit the physician or user toadjust the line left or right depending on where the user visuallyidentifies the correct position to be.

Data points associated with line 12 are then generated by connecting theintersect of detrusor line 90 with the best fit line 10. The data pointsassociated with line 12 are those of a constant pressure value thatextend to the volume point associated with line 16 (max pressure).During this period, the vesicoelastic forces are largely constant whilethe detrusor forces are responsible for the increase in pressure. Oncemax pressure is achieved and begins to reduce, the vesicoelastic forcesare largely reducing in a linear fashion until reaching zero. Thus, datapoints for line 14 are generated by connecting the datapoints at the endof line 12 with the zero pressure reading at the end of the curve. Allof the previously mentioned values associated with the aforementionedlines are generated and stored in the data model for subsequent use bythe program.

Next, in step 86, all the AUC values are calculated by pulling thevarious data points from memory 44 or 43 and calculating the AUC throughknown numerical analysis methods. More specifically, the AUC for lines76, 10, 78, 92, 12 and 14 are calculated and stored. The data for lines10, 12 and 14 are, in one embodiment, that which was posted back afteradjustment by the user or physician in the UX 52. Thereafter, the workperformed by the detrusor is calculated in two parts. First, theAUC_(BC) is calculated by subtracting the summation of the pressures ofline 10 from the summation of pressures for line 76. Next, AUC_(DC) iscalculated by (AUC Line 78-AUC Line 12). By this way, the work done bythe detrusor prior detrusor actuation and during detrusor actuation (andduring micturition) is calculated.

In step 88, the results are displayed to the UX 52. Here, in oneexample, a page is rendered that presents the data in the format asshown in FIG. 8 which includes the rendered graph of P v V, and thecorresponding calculated and actual values as well as the various AUCcalculations.

In the display depicted in FIG. 8, slider bar 90 is movable left andright by a user's interaction (via mouse). Similar to that describedabove, in one aspect, this may be accomplished through scripting on theclient side with post back data to the server side for calculations bythe application layer 54. In response to this, the AUC values arerecalculated to account for the new position and intersection of theslider bar 90 with the best fit line. This permits a medicalpractitioner to visually identify where he or she believes that the lineshould be located where detrusor actuation begins.

Accordingly, a user such as a physician is able to load urodynamicstudies into the presently described system and obtain the amount ofwork generated in the BC phase during fill. As a result, one obtains aquantitative determination of the detrusor work performed during this BCphase thereby providing the physician or user a quantitative means fordetermining how much the detrusor actuates before it reachesmicturition. For example, if the BC work is relatively low, thephysician may determine that the bladder is acting relatively normal.Likewise, if the amount of work done during this phase is large, thephysician may conclude that the patient is suffering from overactivebladder and can prescribe medication or other treatments. Similarly,during drug trials, the physician may treat a patient with a particularmedication, say Botox, and measure the difference in work performedduring this phase before and after treatment. The result is a morequantitative means of determining dysfunction and treatment.

In another aspect, the present invention can be used to determinebladder dysfunction during the micturition phase. For example, thepresent invention may be used with respect to underactive bladder. Here,the total work is determined (AUC MVE+AUC DC) to obtain the total workdone by the bladder during voiding. This total work takes into accountboth vesicoelastic and detrusor contractions. This value is then dividedby the total change in volume from line 90 to the end of line 92. Thisrepresents the total AUC (Work) divided by the total change in volumewhich equals average pressure during voiding. The present embodimentuses an average pressure, instead of a peak pressure, to determinewhether the detrusor is not actuating properly. As such, the presentinventors have determined that the use of an average volume may be morerepresentative of actual issues as it takes into account pressure overchange in volume or time. Such average pressure may be calculated in theAUC DC or AUC MVE phases to identify average pressures in both thedetrusor and vesicoelastic regions.

Referring now to FIG. 9, an illustration of the urodynamic curve isshown and described. In FIG. 9, line 76 is shown having bumps 126. Theserepresent detrusor contractions occurring prior to micturition or line90. In FIG. 10, line 76 is shown without having similar bumps therein.As will be understood, the AUC BE in FIG. 9 will be larger than that inFIG. 10 is a result of these bumps 126. Accordingly, one will understandthat the area under the curve where the detrusor is actuating will belarger than that where it is not.

With continued reference to FIG. 9 and FIG. 10, the total area under thecurve from line 90 to line 92 represents the work performed by thevesicoelastic and detrusor components during micturition. This workdivided by the change in volume from line 90 to line 92 represents theaverage pressure during micturition. In one example, the peak pressurein FIG. 9 represented at line 16 is smaller than the peak pressure shownin FIG. 10. However, the peak pressure in FIG. 10 is concentrated over asmaller change in volume than that of FIG. 9. As such, one may beincorrect in concluding that the peak pressure in FIG. 10, being higher,is more indicative of dysfunction in the bladder. Instead, the presentinvention utilizes the average pressure over the change in volume torepresent an average pressure for identifying dysfunction such asunderactive bladder.

In another embodiment, the data from the data model is used to calculateadditional features for the understanding of the health of the bladder.In one example, the degree in spike (local pressure value relative tothe best fit line is calculated for various points along the curve toidentify specific fluctuations in the detrusor muscle at a local levelto identify at various points during the bladder fill where detrusorcontractions occur). Likewise, the catheter end itself may provideultrasonic, electrical current or vibration or other soniccharacteristics through the saline solution and the pressure orcontractions can be measured to understand bladder characteristics.Also, the data model may be loaded into the database and the bladdercharacteristics can be stored for multiple patients to create a databaseof urological curves that may represent specific conditions.

Uroflowmetry is performed by measuring urine flow using variousapparatus to measure flow. In one aspect, a flow meter is provided thatmeasures the flowrate of urine or other solution exiting the bladder.The flowrate can be measured overtime. As described in previousembodiments, a flow curve is produced which is outlined by the flow ratein the y axis and time in the x axis. Again flow curves represent theprinciples of thermodynamics and the area under the curve isproportional to the work being performed by the bladder. These flowcurves and the distinctive patterns associated with these curves suchas; bell, plateau, tower, interrupted and staccato, in one aspect, arecalculated and used to define certain medical conditions associated withabnormal urination. For example, in one embodiment, the flow rate loadedinto the data model is then used to calculate slopes of the curve atvarious points during urination to determine if the detrusor or otherfeatures of the bladder are excreting at an extremely high rate.

A system to define the slope (acceleration of the initial void to themaximal flow velocity includes or initial acceleration) can be used todefine these diagnostic categories especially when combined with theability to measure the area under the curve.

Relating to FIG. 6, the uroflowmetry curves can be analyzed by drawing aline from the initiation of flow to the point of maximal flow torepresent the average acceleration of fluids exiting the bladder.Another line that measures the maximal acceleration would be or can beincluded as well in the determinations. The area under the curve can becalculated to provide and indication of work being performed or in thiscase the Power of the void (power=work/Δt).

Referring now to FIGS. 12A and 12B, another embodiment of the operationof data processing in step 70 of FIG. 6 is shown and described. In FIG.12A, pressure is shown being charted against volume as described in theprevious embodiments. In step 70, the power exhibited by the bladder 20is charted against time. Here, power is equal to the pressure timesflowrate (multiplied by a constant). The power shown is actually thepower input into the bladder until micturition occurs. Morespecifically, it is the flowrate of the pump pumping saline into thebladder 20 times the pressure in the bladder 20 at each point in time.As such, step 70 uses the pressure, volume and time data to calculatethe change in volume per unit time at every pressure point. FIG. 12Bshows the resulting graph of this power vs time calculation.Specifically, the power steadily increases as the pressure increases ata constant flowrate (due to the constant volumetric flowrate pump) untilthe detrusor muscle actuates at line 90. Thereafter, the power increasesas the constant flowrate pump continues to pump while the pressureincreases due to the detrusor muscle as well as the vesicoelasticconditions in the bladder 20. At this point, the pump is stopped and thepatient is connected to the device shown in FIG. 11 to permitmeasurement of pressure, volume, flowrate and time during micturition.Accordingly, micturition is shown beginning at line 120 where the powerbegins at zero and increases steeply to a maximum power (associated withmaximum pressure in the bladder 20 and maximum flow rate of urineexiting the bladder 20) and then gently degrades as urine exits thebladder 20.

Underactive bladder or UAB is a condition associated with inability tourinate once the bladder reaches micturition pressure and volume. Assuch, the inventors have realized that underactive bladder may exhibitsymptoms of high bladder pressure and low flow rate or high flow rateand low bladder pressure. Therefore, simply measuring pressure may notprovide sufficient means to identify UAB. By using power, a calculationis provided that accounts for both pressure and flow rate. Therefore,the inventors have realized that calculation of power versus timeprovides a good analytical tool to identify underactive bladder as thisprovide an indication of both pressure and flow rate during the timespan of micturition.

For example, with reference to FIG. 12C, two different pressure versusvolume curves are shown during voiding (similar to that of FIG. 12A).Curve 78B exhibits a larger pressure but a smaller change in volumewhile curve 78C exhibits a smaller pressure but a larger change involume. As will be understood, either one of these curves 78B or 78Cwould result in the same power curve as shown in FIG. 12B as the curvein FIG. 12B is a function of both pressure and flowrate and either oneof these curves might exhibit underactive bladder. Thus, comparing thepower curve of the patient to a normal power curve can be used toidentify flowrate and pressure symptoms of underactive bladder.

In FIGS. 13, 14 and 15A and 15B and step 70 of FIG. 6, a furtherembodiment of the present invention is shown and described. In theaformentioned figures, the first law of thermodynamics is used tocalibrate the filling phase and voiding phase. More specifically, theenergy and during filling of the bladder due to vesicoelasticconsiderations is equal the energy out due to vesicoelasticconsiderations. As such, by calculating the energy in during filling,this value can be subtracted from the energy out to compensate fordiffering physiological characteristics of the patient.

For example, in FIGS. 15A and 15B, bladder 20 is shown schematically. InFIG. 15A, the total work or energy input into bladder 20 is equal to AUCMVE during the filling of the bladder 20 on the left side of line 120.This assumes no or relatively little detrusor contractions occur, or,line 10 in FIG. 4 may be used to calculate the AUC MVE prior to line120. Likewise in FIG. 15B, the energy power is equal to MVC DE plus MVCMVE on the right side of line 90. Under the first law of thermodynamics(and excluding heat energy as negligible), AUC MVE on both sides of line90 should be equal. Essentially, this would be equivalent to stretchingand releasing a spring or expanding and contracting a balloon.

By subtracting out AUC MVE calculated on the left side of line 90 orline 120 from the total AUC under line 76 on the right side of line 90,the detrusor contribution is isolated from the total energy on thevoiding side. Therefore, when attempting to quantify valuesrepresentative of underactive bladder, variances based on patientphysiology may be removed and result in a more consistent value andanalysis. For example, an elderly woman with a normal bladder wouldlikely exhibit lower vesicoelastic characteristics than a young male. Assuch, the power and work is calculated on the left side of line 90 canthen be subtracted from the power or work calculated for the right sideof line 90 for the elderly woman and results in simply the detrusorcontractility that may be more consistent across all patients (young,old, male, female). The result is a more standardized means ofdetermining a healthy or unhealthy bladder.

In FIG. 13, a process for utilizing the above approach is described. InFIG. 13, step 70 in FIG. 6 begins by generating the pressure versusvolume curve as described in aforementioned embodiments in step 170. TheAUC MVE is then calculated for the left side of line 90 or line 120. Instep 172, the AUC MVE is then divided by the amount of time during fill.This represents total work done during the fill stage W=dW/dT. Fromthis, it can be assumed that the average power on the void side due tovesicoelastic conditions should be the same. Accordingly, when the powercurve of FIG. 12B is generated, this average power is subtracted fromeach point along the power curve from line 90 until voiding is completein step 174. By this way, a calculation of the true power caused by thedetrusor is determined.

With reference to FIG. 14, another embodiment is shown and described.Here, the pressure versus volume curve is calibrated based on the amountof work calculated during the filling phase. In FIG. 14, the processstarts at step 176 where the AUC MVE is calculated. In step 178, thetotal AUC under line 78 is calculated. In step 180, instead of using theAUC MVE calculated underlines 12 and 14, the AUC calculated in step 176is subtracted from AUC under line 78 to arrive at the AUC DE.

In this specification, various preferred embodiments may have beendescribed with reference to the accompanying drawings. It will, however,be evident that various modifications and changes may be made thereto,and additional embodiments may be implemented, without departing fromthe broader scope of the invention as set forth in the claims thatfollow. The present invention is thus not to be interpreted as beinglimited to particular embodiments and the specification and drawings areto be regarded in an illustrative rather than restrictive sense.

It will be appreciated that the system and methods described herein havebroad applications. The foregoing embodiments were chosen and describedin order to illustrate principles of the methods and apparatuses as wellas some practical applications. The preceding description enables othersskilled in the art to utilize methods and apparatuses in variousembodiments and with various modifications as are suited to theparticular use contemplated. In accordance with the provisions of thepatent statutes, the principles and modes of operation of this inventionhave been explained and illustrated in exemplary embodiments.

It is intended that the scope of the present methods and apparatuses bedefined by the following claims. However, it must be understood thatthis invention may be practiced otherwise than is specifically explainedand illustrated without departing from its spirit or scope. It should beunderstood by those skilled in the art that various alternatives to theembodiments described herein may be employed in practicing the claimswithout departing from the spirit and scope as defined in the followingclaims. The scope of the invention should be determined, not withreference to the above description, but should instead be determinedwith reference to the appended claims, along with the full scope ofequivalents to which such claims are entitled. It is anticipated andintended that future developments will occur in the arts discussedherein, and that the disclosed systems and methods will be incorporatedinto such future examples. Furthermore, all terms used in the claims areintended to be given their broadest reasonable constructions and theirordinary meanings as understood by those skilled in the art unless anexplicit indication to the contrary is made herein. In particular, useof the singular articles such as “a,” “the,” “said,” etc. should be readto recite one or more of the indicated elements unless a claim recitesan explicit limitation to the contrary. It is intended that thefollowing claims define the scope of the invention and that the methodand apparatus within the scope of these claims and their equivalents becovered thereby. In sum, it should be understood that the invention iscapable of modification and variation and is limited only by thefollowing claims.

1. A method performed by at least one processing device (40) and atleast one memory device (40, 43, 46) for analyzing data from aurodynamic study, the method comprising: determining pressure data (76,78, 92) from said urodynamic study that represents a pressure of liquidinside a bladder (20) and storing said pressure data (76, 78, 92) insaid memory device (40, 43, 46); determining volume data from theurodynamic study that represents a volume of said liquid inside saidbladder (20) and storing said volume data in said memory device (40, 43,46); using said processing device (40) to correlate said pressure data(76, 78, 92) with said volume data; determining vesicoelastic pressuredata (10, 12, 14) that represents pressure exhibited by vesicoelasticforces in said bladder (20) correlating said vesicoelastic pressure data(10, 12, 14) with said volume data; and calculating with said processingdevice (40) an amount of vesicoelastic work performed by said bladder(20), wherein the amount of vesicoelastic work performed by the bladder(20) is determined by calculating an area under said vesicoelasticpressure data (10, 12, 14) when said vesicoelastic pressure data (10,12, 14) is correlated against said volume data.
 2. The method performedby at least one processing device (40) and at least one memory device(40, 43, 46) according to claim 1, further comprising: calculating withsaid processing device (40) an amount of detrusor work performed by saidbladder (20); wherein said detrusor work is calculated by saidprocessing device (40) by determining an area between said vesicoelasticpressure data (10, 12, 14) and said pressure data (76, 78, 92).
 3. Themethod performed by at least one processing device (40) and at least onememory device (40, 43, 46) according to claim 1, wherein saiddetermining said volume data further comprises: measuring time data withthe processing device (40); and multiplying the time data by a constant.4. The method performed by at least one processing device (40) and atleast one memory device (40, 43, 46) according to claim 2, furthercomprising: identifying a micturition starting point (120) in thepressure data (76, 78, 92) and the vesicoelastic pressure data (10, 12,14); and identifying a bladder (20) fill starting point of the pressuredata (76, 78, 92) and the vesicoelastic pressure data (10, 12, 14);wherein the detrusor work is calculated between the bladder (20) fillstarting point and the micturition starting point (120).
 5. The methodperformed by at least one processing device (40) and at least one memorydevice (40, 43, 46) according to claim 4, further comprising comparingthe detrusor work against a standard value to determine whether acondition of overactive bladder (20) exists.
 6. The method performed byat least one processing device (40) and at least one memory device (40,43, 46) according to claim 2, further comprising: identifying a voidingendpoint of the pressure data (76, 78, 92); wherein the area between thepressure data (76, 78, 92) and the vesicoelastic pressure data (10, 12,14) is calculated between the micturition starting point (120)s and thevoiding endpoint.
 7. The method performed by at least one processingdevice (40) and at least one memory device (40, 43, 46) according toclaim 1, further comprising: identifying a micturition starting point(120) in the pressure data (76, 78, 92); and identifying a bladder (20)fill starting point of the pressure data (76, 78, 92), wherein thevesicoelastic work is calculated between the bladder (20) fill startingpoint and the micturition starting point (120); and calculating anaverage power from the vesicoelastic work.
 8. The method performed by atleast one processing device (40) and at least one memory device (40, 43,46) according to claim 7, further comprising: identifying a voidingendpoint of the vesicoelastic pressure data (10, 12, 14); calculating anarea under a curve of the pressure data (76, 78, 92) from themicturition starting point (120) to the voiding endpoint; subtractingthe average power from the area under the curve of the pressure data(76, 78, 92) from the micturition starting point (120) to the voidingendpoint to determine detrusor work during voiding.
 9. The methodperformed by at least one processing device (40) and at least one memorydevice (40, 43, 46) according to claim 1, further comprising:identifying a micturition starting point (120) and a voiding end pointin the pressure data (76, 78, 92); and calculating a power curve betweenthe micturition starting point (120) and the voiding endpoint.
 10. Acomputing device for analyzing data from a urodynamic study, the devicecomprising: a memory device (40, 43, 46) configured to store pressuredata (76, 78, 92) from said urodynamic study that represents a pressureof liquid inside a bladder (20); said memory device (40, 43, 46)configured to store volume data from the urodynamic study thatrepresents a volume of said liquid inside said bladder (20); aprocessing device (40) configured to retrieve said pressure data (76,78, 92) from said memory device (40, 43, 46) and using said processingdevice (40) to correlate said pressure data (76, 78, 92) with saidvolume data; said processing device (40) configured to retrieve saidpressure data (76, 78, 92) from said memory device (40, 43, 46) anddetermine vesicoelastic pressure data (10, 12, 14) that representspressure exhibited by vesicoelastic forces in said bladder (20) saidprocessing device (40) configured to correlate said vesicoelasticpressure data (10, 12, 14) with said volume data; and Said processingdevice (40) configured to calculate an amount of vesicoelastic workperformed by said bladder (20), wherein the amount of vesicoelastic workperformed by said bladder (20) is determined by calculating an areaunder said vesicoelastic pressure data (10, 12, 14) (76, 78, 92) whensaid vesicoelastic pressure data (10, 12, 14) is correlated against saidvolume data.
 11. The device according to claim 10, wherein saidprocessing device (40) is further configured to calculate an amount ofdetrusor work performed by said bladder (20); wherein said detrusor workis calculated by said processing device (40) by determining an areabetween said vesicoelastic pressure data (10, 12, 14) and said pressuredata (76, 78, 92).
 12. The device according to claim 11, wherein theprocessing device (40) is further configured to: identify a micturitionstarting point (120) in the pressure data (76, 78, 92) and thevesicoelastic pressure data (10, 12, 14); and identify a bladder (20)fill starting point of the pressure data (76, 78, 92) and thevesicoelastic pressure data (10, 12, 14); and calculate the detrusorwork between the bladder (20) fill starting point and the micturitionstarting point (120).
 13. The device according to claim 12, wherein theprocessing device (40) is further configured to compare the detrusorwork against a standard value to determine whether a condition ofoveractive bladder (20) exists.
 14. A system for analyzing data from aurodynamic study, the system comprising: catheter for insertion into abladder (20) of a patient; a pump for providing a solution into thebladder (20); a computing device connected to the pump and the catheter;a memory device (40, 43, 46) configured to store pressure data (76, 78,92) from said catheter that represents a pressure of liquid inside abladder (20); said memory device (40, 43, 46) configured to store volumedata from said catheter that represents a volume of said liquid insidesaid bladder (20); a processing device (40) configured to retrieve saidpressure data (76, 78, 92) from said memory device (40, 43, 46) andusing said processing device (40) to correlate said pressure data (76,78, 92) with said volume data; said processing device (40) configured toretrieve said pressure data (76, 78, 92) from said memory device (40,43, 46) and determine vesicoelastic pressure data (10, 12, 14) thatrepresents pressure exhibited by vesicoelastic forces in said bladder(20) said processing device (40) configured to correlate saidvesicoelastic pressure data (10, 12, 14) with said volume data; and Saidprocessing device (40) configured to calculate an amount ofvesicoelastic work performed by said bladder (20), wherein the amount ofvesicoelastic work performed by said bladder (20) is determined bycalculating an area under said vesicoelastic pressure data (10, 12, 14)when said vesicoelastic pressure data (10, 12, 14) is correlated againstsaid volume data.
 15. The device according to claim 14, wherein saidprocessing device (40) is further configured to calculate an amount ofdetrusor work performed by said bladder (20); wherein said detrusor workis calculated by said processing device (40) by determining an areabetween said vesicoelastic pressure data (10, 12, 14) and said pressuredata (76, 78, 92).
 16. The device according to claim 15, wherein theprocessing device (40) is further configured to: identify a micturitionstarting point (120) in the pressure data (76, 78, 92) and thevesicoelastic pressure data (10, 12, 14); and identify a bladder (20)fill starting point of the pressure data (76, 78, 92) and thevesicoelastic pressure data (10, 12, 14); and calculate the detrusorwork between the bladder (20) fill starting point and the micturitionstarting point (120).
 17. The device according to claim 16, wherein theprocessing device (40) is further configured to compare the detrusorwork against a standard value to determine whether a condition ofoveractive bladder (20) exists.